The issue is referenced in this thread:

http://forums.sun.com/thread.jspa?threadID=5445370&tstart=0

This simple code

import javafx.animation.Timeline;
import javafx.animation.KeyFrame;
import java.util.Date;
import java.text.SimpleDateFormat;


public function run() {
    def formatter = new SimpleDateFormat("hh:mm:ss a");
    def timeline:Timeline = Timeline {

                repeatCount: Timeline.INDEFINITE
                keyFrames: [
                    KeyFrame {

                        time: 1s
                        action: function() {
                            println(formatter.format(new Date()));
                        }
                    }
                ]
            }
    timeline.playFromStart();

}

Gets this output

06:41:51 PM
06:41:54 PM
06:41:57 PM
06:42:00 PM
06:42:03 PM
06:42:06 PM
06:42:08 PM
06:42:12 PM
06:42:15 PM
06:42:17 PM
06:42:20 PM
06:42:23 PM

So the "tic" is done in 3-4s instead of in 1s. My Computer is a Core 2 Duo E8500 at 3,16Ghz and if I reduce the 1s to 250ms I get the "tics" every second. This code was working for an analog/digital clock on javafx 1.2 and now it doesn't